The aim of this study is to test in a real political context whether or not a change in the beliefs which were fueling the political violence in question is required during the advent of a peace process. Two hypothesis are considered: a) in the case of these beliefs not being modified, there will be difficulties to reach an atmosphere of trust between both parts and the process will fail, and b) if this happens, the groups will develop more extreme beliefs against the opponent. The results obtained through a textual analysis support both hypotheses. During the failure of the peace process, neither the strategy of the delegitimization of the opponent nor the identities in conflict were modified. Consequently, when the process failed, responsibility for this failure was attributed to the opponent, and, at the same time, delegitimization against the opponent intensified.